I noticed that the install process install the kernel includes in /usr/include even though I have installed the kernel's sources. Shouldn't /usr/include/(linux,asm,scsi) be symlinks to /usr/src/linux/include/(linux,asm,scsi) then? Otherwise programs get build with a different version of the include files than kernel version.
programs shouldn't use kernel includes; they should use last major version includes.. there was a huge flame about this on the linux kernel mailing list a few months back.